High-speed electronic digital computers of the type produced by Cray Research, Inc., the assignee hereof, utilize banks of interconnected circuit modules. Each circuit module includes two circuit boards mounted in close proximity on opposite sides of a cooling plate. Each circuit board in turn includes numerous miniaturized logic and memory devices. Computers of this type thus tend to have high circuit densities and numerous input and output signals, connections for which must be provided. Further, the trend is toward computers of greater capacity, increasing circuit densities, and thus even more connections.
A variety of electrical connectors have been available heretofore for use with printed circuit boards, however, there have been certain drawbacks with the prior connectors. For example, the most common approach has been to provide a plug-in type connector consisting of complementary male and female contacts including numerous pins for making or breaking multiple contacts simultaneously. Of course, as the number of pin contacts increases, the insertion force required also increases along with the chances of misalignment and thus damage. It will be appreciated that connectors of this type are not especially tolerant to misalignment and the pins therein can easily become damaged during attempted connection if misaligned even slightly.
U.S. Pat. No. 4,352,533 shows a connector device for printed circuit boards comprising a pair of opposed male portions and an intermediate slidable shuttle portion. The male portions include opposing aligned pins, the pins on one portion being relatively longer than those on the other portion. The female shuttle includes dual entry female contacts which are supported by and moveable along the long pins of one male portion into or out of engagement with the short pins on the other male portion to make or break electrical contact. The shuttle portion is cam actuated, but in mass connect/disconnect fashion.
On the other hand, the PB 18 printed circuit board connector assembly from ITT Cannon of Mountain Valley, Calif., utilizes a cam for sequentially opening or closing pairs of contacts in zipper fashion. This connector, however, utilizes pre-loaded spring contacts which are normally biased toward engagement with finger contact pads on the edge of the PC board. This type of connector is thus a zero-insertive force-type connector, but relies upon spring tension for surface pressure contact, which is not as reliable as a wiping action-type contact. Further, the slider must be left in place to keep the spring contacts open. This connector also tends to be somewhat bulky.
A need has thus arisen for a new and improved ZIP edge connector of more compact construction wherein electrical contact is made or broken sequentially under a wiping action with greater reliability.